#include <bits/stdc++.h>
using namespace std;

class Solution
{
public:
    int main()
    {
        int k;
        cin >> k;
        double sum = 0.0;
        double n = 0.0;
        while (sum <= k)
        {
            n += 1.0;
            sum += 1.0 / n;
        }
        cout << static_cast<long long>(n);
        return 0;
    }
};

#ifndef __LOCAL_TEST__
int main()
{
    return Solution().main();
}
#endif